Circuit breaker



April 1941- L. J. LINDE ET AL 2,240,189

cmcun- BREAKER Filed Sept. 22, 1959 Inventors:

Leonard J. Linde, M Joseph W. Seam. n,

, by 38% Their Attorney.

Patented Apr. 29, 1941 omoUrr BREAKER Leonard J. Linde, Drex Seaman, Upper Darb e1 Hill, and Joseph W.

assignors to General Electric Company, a corporation or New York Application September 22, 1939, Serial No. 296,084

6 Claims.

Our invention relates to circuit breakers, more particularly to manually-operated circuit breakers having current responsive means for open- For a more complete understanding of our in- I vention, reference should be had to theaccompanying drawing in which Fig. 1 is a fragmentary perspective view of a circuit breaker embodying our invention and showing the switch in the closed circuit position; Fig. 2 is a view similar to Fig. 1, but showing the switch in the manually opened position; Fig. 3 is a similar view showing the switch in the automatic open position; while Fig. 4 is a fragmentary view showing a modified form of our invention.

Referring to the drawing in the form shown the circuit breaker comprises a contact arm l preferably made of electrically insulating material having a fixed pivot II and carrying a movable contact l2 which cooperates with a stationary contact l3. This contact arm is actuated by means of a toggle comprising two pairs of links l4 and l 5 connected together by a movable pivot l6. The other ends of the links [4 are connected by a pivot I! to the contact arm III while the other ends of the links are connected to stationary pivots l8 and lBa having a common axis. This pivot I8 is mounted in any suitable manner on supporting plates which, for purposes of clarity, have not been shown. For example, parallel spaced supporting plates may be arranged between the links I5 and handle 26 for supporting the fixed pivot l8.

For purposes of operation, two parallel operating arms l9 and are provided having their upper ends pivoted on the pivot l8 and their lower ends joined by a cross bar 2|. These two arms are each mechanically connected to the adjacent switch member or link l5 so as to normally move with and actuate the links [5. This connection comprises for the arm 13 a latch arm 22 pivoted on a pivot 23 carried by the links I5 intermediate their ends and having its other end normally in abutting engagement with a lateral projection 24 secured to the arm 19. A similar connection, not shown in detail, is provided for the other arm 20. These connections, when the arm 22 engages the projection 24, prevent relative angular movement between the arm l9 and the corresponding switch member or link IE toward each other, while relative angular movement in the opposite direction is prevented by a transverse projection 25 on the upper end of the arm l9 extending over the link IS.

A handle arm 26 is provided having its lower end pivoted on the pivot l8. This handle is connected by the helical overcenter tension spring 21 with the cross bar 2|. Consequently, with the parts in the relative position shown in Fig. 1, movement of the handle toward the left-hand moves the overcenter spring to the left-hand side of the pivot, l8 whereupon. the arms [9 and 20 and the switch members or links l5, secured to them, are snapped in a clockwise direction about the pivot l 8 to the position shown in Fig. 2. This breaks the toggle downward and moves the switch arm 10 to its open circuit position.

Current responsive means are provided for moving the latch arm 22 out of engagement with the projection 24 to thereby open the switch independently of the handle 26. This means comprises suitable current responsive means shown as a loop shaped bimetallic thermostat 28 having a projection 29 on its upper free end which normally engages and holds up a trip lever 30 preferably made of electrically insulating material and having a fixed pivot 3|. 'I'hislever is biased by a spring 32 in a counterclockwise direction, as seen in the drawing, about the pivot 3|. The opposite end of the lever 30 is provided with a pin and slot connection 33 and 34 with an arm 35, the other end of which is mounted on the movable pivot 23.

Normally with the latch lever 30 held by the thermostat as seen in Fig. 1, the pivot 33 is in such position that its axis is coincident with the axis of the fixed pivot I 6. Consequently, when the switch is operated manually, the arm 35 is free to rotate about the pivot 33.

As indicated diagrammatically by the conductors 36, 31 and 33, the bimetallic thermostat is connected electrically in circuit with the contacts I2 and I3. Upon the occurrence of a predetermined maximum current in the switch, the thermostat is heated to such an extent by the current passing through it that its upper end moves toward the left hand far. enough to release the latch lever 30. The lever thereupon is rotated in a counterclockwise direction by the spring 32 whereby the arm 35 is moved about the pivot 23 in a clockwise direction to disengage the I latch arm 22 from the projection 24. Thereupon the toggle is broken downward by a tension spring 3! connecting the bar it with the floating pivot I of the toggle. This opens the switch, the parts being then in the relative positions indicated in Fig. 3.

To reclose the switch, the handle is moved from the position shown in Fig. 3 toward the left hand, i. e., toward the open circuit position. During this movement, a projection N on the handle engages the right-hand end or the latch lever 30, thereby moving it back to its latched position where it is secured by the thermostat, assuming of course that the thermostat has cooled to such an extent that its upper end has returned to a latching position. This also moves the arm 35 downward about the pivot 23, this movement being initially independent or the latch arm 22 which then rests, as shown in the drawing, on the projection 24. As shown, the latch arm 22 has a projection ll bent laterally over the arm 35 so that when the arm 35 is raised, the arm 22 is carried with it to its unlatched position. The arm 35 is free to move, however, against the force of a biasing spring 42 in a counterclockwise direction independently of the arm 22. When the handle 26 has moved far enough for the spring 21 to pass to the left-hand side of the stationary pivot II, the arms 19 and 20 are snapped to their open circuit positions, the spring 39 being stretched since it is weaker than the spring 21. The latch arm 22 then is moved downward behind the projection 24 by its biasing spring 42. The parts now are in the position shown in Fig. 2 and the switch can'be closed as previously described by moving the handle toward the right hand.

It willbe understood that for simplicity and clarity in the description, a single one only has been referred to 01 certain of the parts which are provided in pairs. For example, the arm 20 is arranged in the same manner as the arm IS with a projection, a latch arm, and an arm connected to the latch .lever corresponding to the parts 24, 22 and 35.

While the pivot pin 33 has been disclosed as having an axis coincident with the axis 0! the pivots l8 and Ila, it will be understood that substantial coincidence only is required in view of the fact that the pivot pin 33 may be displaced, ior example, in a direction substantially at right angles to the latch lever 30. In such event, the slot 34 of course will have a curvature corresponding to the radius of movement of the end oi "the arm .35 about the axis of the pins I8 and IDA, This is indicated in Fig. 4 showing a pivot pin 43 and an arm ll which correspond respectively with the pivot pin 33 and the arm 35 of Fig. 1. In Fig. 4 the pivoted pin 4! is displaced downward with respect to the axis of the pivot ll. Due to the displacement of the pin 43 slot H corresponding to the slot ll of Fig. 1, has a curvature corresponding to the are 01' movement of the end of the arm I! about the pivot ll so as to provide for movement of the arm 45 about the pivot ll independently of the pin 0.

While we have shown a particular embodimerit of our invention, it will be understood, 0! course, that we do not wish to be limited thereto, since many modifications may be made and we, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent 01 the United States, is:

1. A circuit breaker comprising a switch member mounted on a pivot for movement between open and closed circuit positions, an operating arm mounted on said pivot, means biasing said switch'member with respect .to said operating arm to said open circuit position, latch means normally securing said switch member against said biasing means in a predetermined relation with said operating arm, means for moving said operating arm to move said switch member between said open and closed circuit positions, current responsive means for actuating said latch means to release said switch member, and a pin and slot pivotal connection between said current responsive means and said latch means.

2. A circuit breaker comprising a switch member mounted on a timed pivot movable between open and closed circuit positions, an operating arm mounted on said pivot, means biasing said switch member with respect to said operating arm to said open circuit position, latch means normally securing said switch member against said biasing means in a predetermined relation with said operating arm, means for moving said operating arm to move said switch member be-- tween said open and closed circuit positions, current responsive means for actuating said latch means to release said switch member, and a pin and slot pivotal connection between said current responsive means and said latch means, said slot being curved to provide for movement of said operating arm and said latch means together in a predetermined relation with respect to each other.

3. A circuit breaker comprising a switch member movable between open and closed circuit positions, an operating arm mounted on a fixed pivot, a spring biasing said switch member with respect to said operating arm to said open circui-t position, latch means normally securing said switch member against said spring in a predetermined angular relation with said operating arm, means for moving said operating arm to move said switch member between said open and closed circuit positions, current responsive means for actuating said latch means to release said switch member, and a pivotal connection between said current responsive means and said latch means having an axis normally substantially coincident with the axis of said fixed pivot to provide for movement of said operating arm and said latch means together in a predetermined relation with respect to each other.

4. A circuit breaker comprising a movable contact, a switch member connected to operate said contact mounted on a fixed pivot, an operating arm mounted on said fixed pivot, a spring biasing said switch member with respect to said operating arm to operate said movable contact to its open circuit position, latch means normally securing said switch member against said spring in a predetermined angular relation with said operating arm, an operating handle, spring means connecting said handle with said operating arm for operation of said operating arm, a trip arm, current responsive means normally holding said trip arm, a pivotal connection between said trip arm and said latch means having an axis normally coincident with the axis of said fixed pivot to provide for movement of said operating arm and said latch means about said axis in a predetermined relation with respect to each other, and means biasing said trip arm to actuate said latch means to release said switch member when said trip arm is released by said current responsive means.

5. A circuit breaker comprising a movable contact, a link connected to operate said contact mounted on a fixed pivot, an operating arm mounted on said fixed pivot, a spring biasing said link with respect to said operating arm to operate said movable contact to its open circuit position, latch means normally securing said link against said spring in a predetermined angular relation withsaid operating arm, an operating handle, an overcenter spring connecting said handle with the free end of said operating arm for operating said arm with a snap action, a trip arm, current responsive means normally securing said trip arm in a predetermined position, a pivotal connection between said trip arm and said latch means having an axis normally coincident with the axis of said fixed pivot to provide for movement of said operating arm and said latch means in a predetermined relation with respect to each other, and means biasing said trip arm to actuate said latch means to release said link when said trip arm is released by said current responsive means.

6. A circuit breaker comprising a pivoted contact arm, a toggle having one link connected to said arm and a second link connected to a fixed pivot, an operating arm mounted on said fixed pivot, a spring biasing said second link withrespect to said operating arm to break said toggle and'move said switch arm to its open circuit position, a latch member pivotally mounted on said second link and normally securing said second link against said spring in a predetermined angular relation with said operating arm, an operating handle having one end pivoted on said fixed pivot, an overcenter spring connecting said handle with the free end of said operating arm for operating said toggle with a snap action, a trip arm, a thermostat normally securing said trip arm in a predetermined position, a pivotal connection between said trip arm and said latch member having an axis normally coincident with the axis of said fixed pivot to provide for movement of said operating arm and said latch memher as a unit in a predetermined relation with respect to each other, and-means biasing said trip arm to actuate said latch arm to release said second link when said trip arm is released by said thermostat.

' LEONARD J. LINDE. JOSEPH W. SEAMAN. 

